Flax seeds are flat, oval and pointed at one end. They contain a seed coating, an embryo comprising two large, flattened cotyledons, a short hypocotyl and a radical. The seed coating in flax seed is formed from the ovule and has five layers, two of which are the most important. These two layers consist of the epidermal layer, commonly called the mucilage layer, and the testa which consists of pigmented cells which determine the seed's coloring. The cotyledon forms 55% of the seed, whereas the seed coat and the endosperm comprise 36% of the seed, while the embryo axis comprises 4% of the seed's total weight.
Typically, various abrasion methods have been implemented in husking. The oil of the flax seed may be separated by pressing or extracting it from the whole grain. Flax seed has been cultivated in Canada and the USA primarily for oil The solid residue has been typically used as an animal feed.
Full fat milled seed is defined as the product milled by any suitable milling process including grinding and impact techniques where the whole seed is milled without any prior extraction of oil or other components.
Defatted flax meal refers to flax meal made from flax seeds from which the oil has been extracted therefrom.
One of the major benefits of processing flax seeds into a nutritional supplement for humans is the fact that they contain lignans in an amount of 0.7 percent to 1.5 percent. High lignan processed flax seeds are believed to hold special pharmaceutical benefits inasmuch as they exhibit broad biological activities, including antitumor, antioxidant, antiviral and estrogenic and antiestrogenic activities. The lignans are generally cinnamic acid dimers containing a dibenzylbutane skeleton. The primary lignan found in flax seed is secoisolariciresinol diglycoside (SDG). Other benefits include the fact that it is a rich source of essential fatty acids.
In the past, lignan concentrations in flax seed were exhibited far less than 3%. In such concentrations, the pharmaceutical applications were more limited and flax seed products were not typically used for antitumor, antiviral, estrogenic and antiestrogenic purposes. It should be noted that in the past, defatted flax seed meals typically contained less than 3 percent lignans.